The methods of chemical information retrieval of structural data and the crystallographic study of receptor plus substrate interactions are being directed to the area of drug design. A particular question can be answered by both methods: What are the spatial and electronic interactions of chemical groups at the level of molecular recognition and binding? Because these methods are essentially numeric, interactive computer graphics is used to let the investigator keep visual control of the modelling and refinement procedures. The enzyme, elastase, has been chosen to serve as the receptor, to which substrates can be bound and studied crystallographically. The model of elastase will be refined with 1.7A crystallographic data. The results of these studies may then be used to predict potential inhibitors of transition state analogs that might have medicinal use when directed against cell degradation diseases, e.g., emphysema.